Only your friend can do anything about the closure. They should have received an email at the address on the account about the options they had.
That said, discussions of cheating, potential cheating, or cheat detection are not allowed in the general forums.
One of my friend's account, that being, ANDRESANTY was recently closed for cheating. Overall, this accusation if probobly a very misinformed one as I am positive that ANDRESANTY wasn't in-fact cheating and that he is, overall, simply a good player in faster time controls. Additionally, he is an un-official Fide CM who has the capability to play very well online. May you please look deeper into his case @moderators. Hopefully we can come to some understanding over this matter.